In this article, we will learn how to disable an item (option) using C#. After disabling it, the user will not be able to select the DropDownList.

How to Disable a DropDownList first item in Asp.Net using C#

Let’s create a simple table ‘customers’ as shown below:

CustomerId (INT),
CustomerName (NVARCHAR 50)
CustomerEmail (NVARCHAR 50)

SQL 

SET ansi_nulls ON 
go 

SET quoted_identifier ON 
go 

CREATE TABLE [dbo].[customers] 
  ( 
     [customerid]    [INT] IDENTITY(1, 1) NOT NULL, 
     [customername]  [NVARCHAR](50) NULL, 
     [customeremail] [NVARCHAR](50) NULL 
  ) 
ON [PRIMARY] 

go

HTML

Now create a Webpage and add a DropDownList control to it, which will be populated from the database.

    <asp:DropDownList ID = "ddlCustomers" runat="server">
    </asp:DropDownList>

You will need to import the following namespaces:

   using System.Data;
   using System.Data.SqlClient;

Once the DropDownList is populated with the data, a default item is inserted at the first position and is selected. Then the default item is disabled by setting the ‘disabled’ attribute of the item.

public partial class _Default : Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            string conn_str = "Data Source=ServerName;Initial Catalog=dbName;Integrated Security=True";
            using (SqlConnection con = new SqlConnection(conn_str))
            {
                using (SqlCommand cmd = new SqlCommand("SELECT * FROM Customers"))
                {
                    cmd.CommandType = CommandType.Text;
                    cmd.Connection = con;
                    con.Open();
                    ddlCustomers.DataSource = cmd.ExecuteReader();
                    ddlCustomers.DataTextField = "CustomerName";
                    ddlCustomers.DataValueField = "CustomerId";
                    ddlCustomers.DataBind();
                    con.Close();
                }
            }
            ddlCustomers.Items.Insert(0, new ListItem("Select a customer", ""));
            ddlCustomers.Items[0].Attributes["disabled"] = "disabled";
        }
    }

}

Related Articles